共查询到20条相似文献,搜索用时 15 毫秒
1.
Sourov Roy 《Pramana》2000,55(1-2):271-276
I briefly review a scenario where R-parity is explicitly broken through a term bilinear in the lepton and Higgs superfields in the superpotential. An immediate
consequence of the presence of this term is the generation of a massive neutrino at the tree level. Constraints on the parameter
space are discussed in the context of recent super-Kamiokande results on atmospheric neutrinos. The testability of such models
is emphasized through the observation of comparable numbers of muons and taus, produced together with the H−-boson, in decays of the lightest neutralino. Some other phenomenological implications of such a scenario are also discussed. 相似文献
2.
C. Adloff et al. 《The European Physical Journal C - Particles and Fields》2001,20(4):639-657
A search for squarks in R-parity violating supersymmetry is performed in collisions at HERA at a centre of mass energy of 300 GeV, using H1 data corresponding to an integrated luminosity of 37 pb. The direct production of single squarks of any generation in positron-quark fusion via a Yukawa coupling is considered, taking into account R-parity violating and conserving decays of the squarks. No significant deviation from the Standard Model expectation is found.
The results are interpreted in terms of constraints within the Minimal Supersymmetric Standard Model (MSSM), the constrained
MSSM and the minimal Supergravity model, and their sensitivity to the model parameters is studied in detail. For a Yukawa
coupling of electromagnetic strength, squark masses below 260 GeV are excluded at 95% confidence level in a large part of
the parameter space. For a 100 times smaller coupling strength masses up to 182 GeV are excluded.
Received: 28 February 2001 / Published online: 29 June 2001 相似文献
3.
The H Collaboration 《The European Physical Journal C - Particles and Fields》2004,36(4):425-440
A search for squarks in R-parity violating supersymmetry is performed in
collisions at HERA using the H1 detector. The data were taken at a centre-of-mass energy of 319 GeV and correspond to an integrated luminosity of 64.3 pb-1 for e
+
p collisions and 13.5 pb-1 for e
-
p collisions. The resonant production of squarks via a Yukawa coupling
is considered, taking into account direct and indirect R-parity violating decay modes. No evidence for squark production is found in the multi-lepton and multi-jet final state topologies investigated. Mass dependent limits on
are obtained in the framework of the Minimal Supersymmetric Standard Model. In addition, the results are interpreted in terms of constraints on the parameters of the minimal Supergravity model. At the
confidence level squarks of all flavours with masses up to 275 GeV are excluded in a large part of the parameter space for a Yukawa coupling of electromagnetic strength. For a coupling strength 100 times smaller, masses up to 220 GeV can be ruled out.Received: 16 March 2004, Revised: 24 May 2004, Published online: 30 July 2004 相似文献
4.
5.
Peiying Li Gongru Lu Jin Min Yang Huanjun Zhang 《The European Physical Journal C - Particles and Fields》2007,51(1):163-168
In the minimal supersymmetric standard model the R-parity violating interactions can induce anomalous top pair productions
at the LHC through the t-channel process dRd̄R→tLt̄L by exchanging a slepton or by the u-channel process dRd̄R→tRt̄R exchanging a squark. Such top pair productions with a certain chirality cause top-quark polarization in the top pair events.
We found that at the LHC, due to the large statistics, the statistical significance of the polarization observable, and thus
the probing ability for the corresponding R-parity violating couplings, is much higher than at the Tevatron upgrade.
PACS 14.65.Ha; 14.80.Ly 相似文献
6.
7.
8.
Abazov VM Abbott B Abdesselam A Abolins M Abramov V Acharya BS Adams DL Adams M Ahmed SN Alexeev GD Alton A Alves GA Amos N Anderson EW Arnoud Y Avila C Baarmand MM Babintsev VV Babukhadia L Bacon TC Baden A Baldin B Balm PW Banerjee S Barberis E Baringer P Barreto J Bartlett JF Bassler U Bauer D Bean A Beaudette F Begel M Belyaev A Beri SB Bernardi G Bertram I Besson A Beuselinck R Bezzubov VA Bhat PC Bhatnagar V Bhattacharjee M Blazey G Blekman F Blessing S Boehnlein A Bojko NI Borcherding F 《Physical review letters》2002,89(17):171801
We present results of a search for R-parity-violating decay of the neutralino chi;01, taken as the lightest supersymmetric particle, to a muon and two jets. The decay proceeds through a lepton-number violating coupling lambda(')(2jk) (j=1,2; k=1,2,3), with R-parity conservation in all other production and decay processes. In the absence of candidate events from 77.5+/-3.9 pb(-1) of data collected by the D0 experiment at the Fermilab Tevatron in pp collisions at sqrt[s]=1.8 TeV, and with an expected background of 0.18+/-0.03+/-0.02 events, we set limits on squark and gluino masses within the framework of the minimal low-energy supergravity-supersymmetry model. 相似文献
9.
Biswarup Mukhopadhyaya 《Pramana》2000,54(1):147-154
Motivated by the recent super-Kamiokande results on atmospheric neutrinos, we incorporate massive neutrinos, with large angle
oscillation between the second and third generations, in a theory with R-parity violating supersymmetry. The general features of such a theory are briefly reviewed. We emphasize its testability
through the observation of comparable numbers of muons and taus, produced together with the W-boson, in decays of the lightest neutralino. A distinctly measurable decay gap is another remarkable feature of such a scenario. 相似文献
10.
《中国科学:物理学 力学 天文学(英文版)》2010,(11)
This paper briefly reviews the lepton flavor violating Z-decays at GigaZ as a probe of supersymmetry by focusing on Z → i j in two representative supersymmetric models: the minimal supersymmetric model without R-parity and the supersymmetric seesaw model.The work concludes that under the current experimental constraints from LEP and i → j γ,these rare decays can still be enhanced to reach the sensitivity of the GigaZ.Therefore,supersymmetry can be probed via these decays at GigaZ. 相似文献
11.
R.M. Wang G.R. Lu E.-K. Wang Y.-D. Yang 《The European Physical Journal C - Particles and Fields》2006,47(3):815-831
We study the branching ratios, the direct CP asymmetries in B→K(*)K̄(*) decays and the polarization fractions of B→K*K̄* decays by employing the QCD factorization in the minimal supersymmetric standard model with R-parity violation. We derive
the new upper bounds on the relevant R-parity violating couplings from the latest experimental data of B→K(*)K̄(*), and some of these constraints are stronger than the existing bounds. Using the constrained parameter spaces, we predict
the R-parity violating effects on the other quantities in B→K(*)K̄(*) decays which have not been measured yet. We find that the R-parity violating effects on the branching ratios and the direct
CP asymmetries could be large; nevertheless their effects on the longitudinal polarizations of B→K*K̄* decays are small. Near future experiments can test these predictions and shrink the parameter spaces.
PACS 12.60.Jv; 12.15.Mm; 12.38.Bx; 13.25.Hw 相似文献
12.
A search for pair-produced sfermions, the scalar supersymmetric partners of the Standard Model fermions, under the assumption that R-parity is not conserved has been performed using data collected with the OPAL detector at LEP. The data samples analysed correspond to an integrated luminosity of about 610 pb-1 collected at centre-of-mass energies of
GeV. An important consequence of R-parity violation is that the lightest supersymmetric particle is expected to be unstable. Searches for R-parity violating decays of charged sleptons, sneutrinos and squarks have been performed under the assumptions that the lightest supersymmetric particle decays promptly and that only one of the R-parity violating couplings is dominant for each of the decay modes considered. Such processes would yield final states consisting of leptons, jets, or both, with or without missing energy. No significant signal-like excess of events has been observed with respect to the Standard Model expectations. Limits on the production cross-sections of sfermions in R-parity violating scenarios are obtained. Constraints on the supersymmetric particle masses are also presented in an R-parity violating framework analogous to the Constrained Minimal Supersymmetric Standard Model.Received: 25 June 2003, Published online: 13 February 2004 相似文献
13.
14.
We present the full result for the down squark mass-squared matrix in the complete theory of supersymmetry without R parity where all kinds of R-parity violating terms are admitted without bias using an optimal parametrization. The major result is a new contribution to LR squark mixing, involving both bilinear and trilinear R-parity violating couplings. Among other things, the latter leads to neutron electric dipole moment at one-loop level. Similar mechanisms lead to electron electric dipole moment at the same level. We present here a short report on major features of neutron electric dipole moment from supersymmetry without R parity and give the interesting constraints obtained. 相似文献
15.
A search for pair produced scalar fermions with couplings that violate R-parity has been performed using a data sample corresponding to an integrated luminosity of 56 pb at a centre-of-mass energy of 183 GeV collected with the OPAL detector at LEP. An important consequence of R-parity breaking interactions is that the lightest supersymmetric particle is expected to be unstable. Searches for R-parity violating decays of charged sleptons, sneutrinos and stop quarks have been performed under the assumptions that the
lightest supersymmetric particle decays promptly and that only one of the R-parity violating couplings is dominant for each of the decay modes considered. Such processes would yield multi-leptons,
jets plus leptons or multi-jets, with or without missing energy, in the final state. No significant excess of such events
has been observed. Limits on the production cross-sections of scalar fermions in R-parity violating scenarios are obtained. Mass exclusion regions are also presented in the framework of the Constrained Minimal
Supersymmetric Standard Model.
Received: 16 March 1999 / Published online: 14 October 1999 相似文献
16.
G. Abbiendi et al. 《The European Physical Journal C - Particles and Fields》1999,11(4):619-642
Searches for pair-produced charginos and neutralinos with R-parity violating decays have been performed using a data sample corresponding to an integrated luminosity of 56 pb collected with the OPAL detector at LEP at a centre-of-mass energy of 183 GeV. An important consequence of R-parity violation is that the lightest supersymmetric particle becomes unstable. The searches have been performed under the
assumptions that the lightest supersymmetric particle promptly decays and that only one R-parity violating coupling is dominant for each of the decay modes considered. Such processes would yield multiple leptons,
jets plus leptons, or multiple jets with or without significant missing energy in the final state. No excess of such events
above Standard Model backgrounds has been observed. Limits are presented on the production cross-sections of gauginos in R-parity violating scenarios. Limits are also presented in the framework of the Minimal Supersymmetric Standard Model.
Received: 14 December 1998 / Published online: 14 October 1999 相似文献
17.
18.
19.
《Nuclear Physics B》2001,600(1):39-61
We discuss the phenomenology of the lightest neutralino in models where an effective bilinear term in the superpotential parametrizes the explicit breaking of R-parity. We consider supergravity scenarios where the lightest supersymmetric particle (LSP) is the lightest neutralino and which can be explored at LEP2. We present a detailed study of the LSP decay properties and general features of the corresponding signals expected at LEP2. We also contrast our model with gauge mediated supersymmetry breaking. 相似文献